package com.example.crashdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
      final Button button =  (Button) findViewById(R.id.bt);
      button.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View arg0) {
			String ss = null;
		      button.setText(ss.substring(0).toString());
		}
	});
    }


   
}
